20 Jul 2007
Researchers from Australia and China describe a simple scheme for simultaneous local and global strain measurements by multiplexing fiber-optic white light interferometric (FOWLI) and fiber Bragg grating (FBG) sensors in the spectral domain.
The multiplexing of different types of fiber-optic sensors to realize simultaneous multi-point, multi-parameter measurements on both local and global scales is a key component for smart monitoring technology.
Many proposed multiplexing schemes are quasi-point sensors, making it difficult for these schemes to realize local and global strain measurements. The researchers believe that these problems can be overcome by multiplexing long-gauge FOWLI sensors and quasi-point FBG sensors (Meas. Sci. Technol. 18 2681-2685).
The researchers describe the assembly of a sensor system with two FOWLIs and two FBGs, which they used to measure the strain of a special plastic specimen. The experimental results demonstrate that the system exhibits low crosstalk and can be readily used to realize local and global strain measurements at the same time.
The compacted system is completely passive and is expected to find applications monitoring aerospace and civil structures as part of smart structure technology.